Determine if string is in Enum in VB.NET

I have an enum like this (in C#)

public enum Cars
{
    Toyota = 'T',
    Honda = 'H',
    Ford= 'F'
}

And a variable for myCar in VB

 Dim myCarValue As String = "H"

How can I check to see if myCarValue is one of the valid values in the Cars enum without comparing comparing against every value in the email? Is there a way to use Contains() to do this?

>Solution :

You can use only numeric types in Enums. This code does simply not compile. You will get the compiler error:

Conversion from ‘String’ to ‘integer’ cannot occur in a constant expression

You must choose a different approach. I suggest using constants and a HashSet(Of String) to store them:

Public Module Cars
    Public Const Toyota = "T", Honda = "H", Ford = "F"

    Private ReadOnly _values As HashSet(Of String) = New HashSet(Of String) From {
        Toyota,
        Honda,
        Ford
    }

    Public Function IsValidValue(carCode As String) As Boolean
        Return _values.Contains(carCode)
    End Function
End Module

Now you can do a check like:

Dim myCarValue As String = "H"
If Cars.IsValidValue(myCarValue) Then

End If

You can also get a specific value with

Dim myCarValue As String = Cars.Toyota

This is very much how you would do it with an Enum.

If the values always consists of a single character, you could also declare the Enum as:

Enum Cars
    Totota = Asc("X")
    Honda = Asc("H")
    Fors = Asc("F")
End Enum

But then the check gets a bit ugly:

If System.Enum.IsDefined(Of Cars)(Asc(myCarValue)) Then

End If

Note that in C# single quotes denote the System.Char type (C#: char, VB: Char) which is considered to be a 16-bit numeric type (like System.Short) and is implicitly converted to an Integer in C#.